Atherosclerosis, an inflammatory disease associated with the production and degradation of the extracellular matrix (ECM) and accumulation of lipids in the arterial wall, is the leading cause of morbidity and mortality worldwide. Substantial epidemiological evidence indicates that particulate and gaseous air pollutants are associated with adverse human health effects, specifically increased rates of cardiovascular incidents. However, the mechanistic cellular and molecular pathways involved in the effects of inhaled environmental air pollutants on the progression of cardiovascular disease have not yet been elucidated. Remodeling of arterial ECM is a crucial step in the progression of atherosclerosis, which is thought to be primarily regulated through matrix metalloproteinase (MMP) expression and activity. However, it has not yet been determined whether MMP activity is involved in the progression of atherosclerosis in association with exposure to common environmental air pollutants. The goal of this proposal is to test the hypothesis that chronic exposure to environmental air pollutants, specifically gasoline engine emissions, results in upregulation of reactive oxygen species (ROS) and subsequent induction of molecular pathways involved in the progression of atherosclerosis. For the purpose of the experiments proposed, herein, we will utilize the animal model of atherosclerosis-prone ApoE knockout mice. In Aim 1, it will be determined whether subchronic exposure to gasoline engine exhaust results in upregulation and subsequent activation of the MMP pathway.which is associatiated with the progression of atherosclerosis. To do this, we will look at the expression and activity of specific members of the MMP proteinase family that have previously been found to be upregulated in the pathogenesis and progression of atherosclerosis. In Aim 2, we will attempt to identify which pathways are involved in induction of MMPs. Specifically we will target the production of ROS, and vasoactive peptide endothelin-1 (ET-1). Additionally, we will determine whether ET-1 expression is being mediated through a ROS (via antioxidant therapy) pathway in atherosclerotic vessels exposed to gasoline engine emission. Finally, in Aim 3, it will be determined whether ET-1 is directly regulating MMP expression and activation by utilizing an ET-1 receptor antagonist therapy in conjunction with the exposures. Considering the ramifications of cardiovascular disease diagnosis and treatment on health care today, it is critical to determine which factors may contribute to the onset and/or progression of such diseases. Identification of environmental factors, and the cellular pathways they potentate, associated with cardiovascular disease progression is critical for both prevention and pharmacological therapy. [unreadable] [unreadable] [unreadable]